The present invention relates to portable computer systems, and in particular to the management of performance and power consumption in a portable computer.
Portable computer systems have always lagged their desktop counterpart personal computers in speed and overall performance due to the limited power available in current batteries. Because the latest and fastest computer components, such as processors consume more power and generate more heat than lower speed components, they are not normally used in portable computer systems such as laptop computers. The use of high speed central processing units (CPUs) requires higher clock speed and higher voltages than current CPUs used for portable computer systems because the higher clock speed and higher operating voltage results in more power being consumed and thus heat being generated. The cooling of such components requires greater power, or larger heat sinks, which is readily available in larger desktop type computer systems.
Due to space constraints, thermal considerations and limited battery life, some portable computers employ various power management methods to reduce generation of heat while operating on battery power such that fans are not activated. Such methods include the reduction of the speed of the processor. When AC power is provided, the processor may run at higher speed and/or higher voltage, however, the cooling capability may not be sufficient to properly cool a portable computer using the current fastest processors and other components. Either there is not sufficient room for a large enough heat sink for the processor, or a large enough fan would consume so much power that the battery would not last long enough to meet current user expectations.
There is a need for a portable computer which can utilize the faster processors that generate more heat than can currently be dissipated by portable computers. There is a further need to operate such processors at higher speed at selected times. There is yet a further need to provide such abilities without using larger heat sinks or other solutions that would increase the size and or weight of such portable computers.
A portable computer receives additional cooling capabilities from an external docking station. The portable computer detects such cooling capacity and modifies its performance. In one embodiment, the portable computer system has a case with openings placed in alignment with mating openings in a docking station which provides additional active cooling capacity. The portable computer system case also has further openings and a defined air flow path to enhance airflow across a processor to cool it more effectively.
In one embodiment, the active cooling provided by the docking station is a fan, or other device which pulls or pushes air from or into the portable computer system case. The mating openings and further openings in the computer system case are positioned to optimize the cooling effectiveness of the air flow with respect to the processor and other heat producing components. Further active cooling apparatus include a compressor coupled to refrigeration coils positioned beneath the portable computer, and other devices which provide active cooling such as by refrigeration or sound and diaphragm combinations. Still further embodiments utilize heat pipes positioned proximate the processor of the portable computer and functioning to transfer heat to the docking station where active heat transfer is provided. Yet further embodiments utilize extruded aluminum slugs to transfer heat from the bottom of the portable computer to the active cooling mechanism provided in the docking station.
In one embodiment, power management functions of the computer system are alerted that the portable computer has been docked with the docking station. Once alerted, the power management functions allow the processor to operate at higher speed, relying on the extra cooling capacity provided by the docking station to properly cool the processor. In a further embodiment, the power management functions simply rely on temperature sensing to control the processor speed.
The extra cooling capacity provided by the docking station then allows the processor to run indefinitely at higher speed. The extra cooling capacity may also provide the ability to utilize faster, more expensive processors which generate more heat without sacrificing the power of the processor when docked. It further enhances the ability to obtain desktop performance from a docked portable computer, while retaining the ability to slow the CPU speed, and/or operating voltage to obtain longer battery life when undocked.